Bass system for automatic root fifth and pedal sustain

ABSTRACT

An improved system is provided for automatically playing bass notes for root and fifth parts of manually held accompaniment chords, including diminished and augmented chords, and for performing pedal sustain keying functions. Latching circuits are provided which respond to actuation of playing keys or pedals and which store the response to the last pedal actuated. The system also includes circuitry for keying bass tones for actuated pedals and for the root and fifth parts of manually played chords. This circuitry includes a set of gates which are each enabled by an associated latching circuit, inhibited by other latching circuits, and inhibited by outputs from other operated gates. The system further includes keying bus sensing and controllable ratio frequency dividers to cover a multiple octave range and to reduce the number of pins required for an integrated circuit pack to implement the system.

United States Patent 1191 Freeman BASS SYSTEM FOR AUTOMATIC ROOT Nov. 25, 1975 3,764,723 10/1973 Takeyama 84/l.0l FIFTH ND PE 3,766,305 10/1973 Schrecongost 84/l.01

A DAL SUSTAIN 3,781,450 12/1973 Nakajima 84/l.0l 6] Inventor: Alfred B-Freemam20418 Seaboard 3,790,693 2/1974 Adachi ..84/1.01 Road, Malibu, Calif. 90265 3,808,344 4/1974 lppolito et a1. 84/1.0l 2 Fl (1: [2 1 l e Apr 1973 Primary ExaminerStephen J. Tomsky [21] Appl. No.: 354,211 Assistant ExaminerStanley J. Witkowski 52 US. Cl. s4/1.01; 84/1.03; 84/1.17; [57] ABSTRACT 4 DIG. 22- 4 DI 5 An improved system is provided for automatically 8 G 2 1511 1m. 01. c1011 1/00; c1011 5/02 P y bass notes for root and fifth Parts of manually [58] Field of Search 84/1.01, 1.03, 1.17, 1.24, held accompaniment chords, including diminished and 84/D1G. 22 DIG 2 DIG 25 augmented chords, and for performing pedal sustain keying functions. Latching circuits are provided which 5 References Cited respond to actuation of playing keys or pedals and UNITED STATES PATENTS which store the response to the last pedal actuated. The system also includes circuitry for keying bass g tones for actuated pedals and for the root and fifth 3548066 12/1970 6 parts of manually played chords. This circuitry in- 3 567 838 3 1971 Tennes e;';;i'.'IIIIIIIiIiIIIII I: 84/1i0l cludes a gates which are each enabled by 3 70 37 12 1972 Al-Sem et aL 1/103 sociated latching circuit, inhibited by other latching 3 703 04 19 3 Hebeisen er 1 34/103 circuits, and inhibited by outputs from other operated 3,711,618 1/1973 Freeman 84/1.03 gates. The system further includes keying bus sensing 3,712,950 1/1973 Freeman 84/1.03 and controllable ratio frequency dividers to cover a 3,715,442 2/1973 Freeman 84/1.01 ltipl ctave range and to reduce the number of pins required for an integrated circuit pack to impleou ar 1 3,760,358 9/1973 151i etal. 84/1.01 x mm the system 3,764,722 10/1973 Southard 84/ 1.03 Claims, 4 Drawing Figures iii/hit l 1 l7 2, /4 I PEDAL /5 la KEYBOARD f MANUAL KEYBOARD /.9 32

28 Y id id 31 l 5 y "35 I2 37 36 39 40 OUTPUT GEMS AUTOMATIC BASS LOGIC a KEYING @21 3 i ,3 4,45 42 TRANSDUCER AUTOMATIC 43 RHYTHM Sheet 2 of4 US. Patent Nov. 25, 1975 US. Patent N0v.25, 1975 Sheet3of4 3,921,491

BASS SYSTEM FOR AUTOMATIC ROOT FIFTH AND PEDAL SUSTAIN BACKGROUND OF THE INVENTION 1. Field of the Invention This invention is directed to an improved system for the automatic playing of bass notes for the root and fifth parts of manually played chords which also has the capability of playing bass notes with sustain in response to actuation of pedals.

2. Description of the Prior Art My U.S. Pat. No. 3,548,066 discloses a system in which bass notes are played automatically in a number of different modes of operation. In one of these modes, the root and fifth parts of the manually played chords are sounded one at a time in the bass. In another mode, each of the manually held notes is sounded in the bass in turn. The first mode does not handle all possible combinations of actuated playing keys and does not play diminished and augmented fifth parts in the bass. The second mentioned mode does not restrict its playing to the root and fifth parts.

US. Pat. No. 3,548,066 further uses electrolytic capacitors to store the keying signal after the last pedal is released so the bass signal may be sustained and allowed to decay naturally. Many electronic organs use similar means to store keying signals for bass sustain. These organs usually obtain the keying signals from interconnected sets ofpedal operated switches which can provide only one keying signal at a time.

My U.S. Pat. No. 3,712,950 uses a controllable ratio frequency divider to produce two bass notes in perfect fifth relation from one signal input for automatic bass playing. This apparatus also does not play diminished and augmented fifth parts and does not handle all comfor automatically playing bass notes and chords by tun-.

ing a chord tone generator according to the root and type of chord being played on a keyboard. This system plays diminished fifths but does not handle all combinations of actuated playing keys and further would be uneconomical for playing bass notes only.

None of the aforementioned systems changes response from pedals to playing keys and vice versa. At least twelve connections would have to be changed or switched to make such a change.

It is, therefore, an object of the present invention to provide an improved bass playing system which can be switched from playing bass automatically in response to manually held accompaniment chords to playing normal electronic organ bass with sustain in response to pedal actuation.

A further object of the present invention is to provide a system of the aforementioned type which does not require electrolytic capacitors, which can be implemented by integrated circuits, and which further requires a minimum number of input connections and so minimizes the number of pins on the circuit pack.

Another object of the present invention is to provide an improved system for automatically playing the root and fifth parts of manually held chords including diminished and augmented chords.

Other objects and advantages of the present invention will become apparent as the description proceeds.

BRIEF SUMMARY OF THE INVENTION In accordance with the present invention, an improved system is provided for automatically playing bass notes for the root and fifth parts of manually held chords and for sustain keying of bass notes in response to pedal operation. A plurality of latching circuits is provided, with each of the latching circuits being associated with one of the notes of a musical scale. A pluralityof gates is provided which are responsive to operation of the latching circuits and which control the production of bass notes.

In the illustrative embodiment, the latching circuits receive inputs from both playing keys and pedals and respond to those having associated keying busses energized. When responding to playing keys,.the latching circuits set and reset as their associated playing keys are operated and released. When responding to pedals, the latching circuits set in response to actuation of their associated pedals and reset when other pedals are actuated after their associated pedal is released. The latching circuit for the last pedal actuated thus remains set until the next pedal is actuated. In the illustrative embodiment, gates associated with the notes of the musical scale receive an enabling input from their associated latching circuits and inhibiting inputs from other latching circuits. The gates also receive inhibiting inputs from other gates of the set. Means is further provided for determining which of the operated gates represents the root part, and for producing bass notes corresponding to the operated gates.

In the illustrative embodiment, controllable ratio frequency dividers are used in combination with sensing of actuated playing keys or pedals with keying bus sections to extend the octave ranges of bass notes played in correspondence with the range of playing keys or pedals. Controllable ratio frequency dividers are also used to obtain two bass notes from one tone signal, thus further reducing the number of input pins required on an integrated circuit pack to implement the system.

A more detailed explanation of the invention is provided in the following description and claims, and is illustrated in the accompanying drawings.

BRIEF' DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of an automatic bass playing system including a pedal sustain keying capability in accordance with the principles of the present invention; and

FIGS. 2a, 2b, and 2c connect together to form a partial schematic and partial block diagram of an embodiment of the system of FIG. 1.

DETAILED DESCRIPTION OF THE ILLUSTRATIVE EMBODIMENT FIG. 1 shows a manual keyboard 11, which may be part of an electronic organ or other keyboard instrument, providing electrical control outputs for each of the twelve notes of the musical scale through resistors 12 to automatic bass logic and keying unit 13. Pedal keyboard 14 likewise provides electrical control outputs for the twelve notes via cable 15 directly to the same inputs of bass logic and keying unit 13. PEDAL/- MANUAL switch 16 applies keying potential to pedal keyboard 14 when it is in the position shown, and bass logic and keying unit 13 then responds to pedal keyboard 14. When switch 16 is in its other position, it applies keying potential to keyboard 11 and bass logic and keying unit 13 then responds to keyboard 11.

NPN transistors 17 and 18 have a negative supply potential applied to their emitters when switch 16 is in the position shown. Line 19 from bass logic and keying unit 13 is then also connected to the collector of transistor l8 by switch 16. The collector of transistor 17 connects .to the base of transistor 18 and the emitter of transistor 20 to the base of transistor 17. Lines 21 and 22 connect from the bases of transistors 17 and respectively to provide keying potential for the first and second octaves respectively of pedal keyboard 14. Resistors 23 and 24 connect the collectors of transistors 17 and 18 respectively to ground while the collector of transistor 20 connects to bass logic and keying unit 13.

With switch 16 in the position shown, actuation of a pedal of keyboard 14 will apply the potential on line'21 or 22 to the associated note input of bass logic and keying 13. If the pedal is in the first octave range, current will be drawn via line 21 from the base of transistor 17. This current will pull transistor 17 into saturation and thus remove the base drive from transistor 18. Transistor 18, which was previously held in saturation by the base drive it was receiving through resistor 23, then cuts off and the voltage on its collector to line 19 goes from the negative supply potential to ground potential through resistor 24. If the pedal is in the second octave range, transistor 20 is pulled into saturation by the current from its base via line 22. The voltage on line 25 to bass logic and keying 13 is then pulled negative by the collector of transistor 20 indicating that a pedal in the second octave range has been actuated. Transistor 17 is also pulled into saturation by the current through its base to the emitter of transistor 20 and base drive is thereby removed from transistor 18. Transistor 18 thus cuts off when any pedal in either octave range is operated and line 19 then goes to ground potential.

When pedal manual switch 16 is in its other position, the negative supply potential is switched from the emitters of transistors 17 and 18 to the emitters of transistors 26, 27, and 28 and line 19 is connected directly to ground. This disables pedal keyboard 14 and enables manual keyboard 11 to control bass logic and keying 13. The lowest octave of keyboard 11 receives keying potential directly from switch 16 via line 29. Successive sections of keyboard 11 receive keying potentials via lines 30, 31, and 32 respectively from the bases of transistors 26, 27, and 28 respectively. Transistors 26, 27, and 28 will be pulled to saturation when playing keys of keyboard 11 in their respective sections are actuated. The collectors of transistors 26, 27, and 28 connect via lines 33, 34, and 35 respectively to bass logic and keying 13 to provide indications indicate playing keys in the respective sections are actuated.

Tone generators 36 provide a set of tone signals via cable 38 to bass logic and keying 13. The set may include a tone signal for each note of the musical scale or may include a lesser number if bass logic and keying 13 has a capability of dividing by different ratios and thus providing signals for more than one bass note from one tone signal. This capability reduces the number of inputs required to bass logic and keying l3 and hence the number of pins required for an integrated circuit pack to provide the bass logic and keying 13 functions. The capability of dividing by different ratios is also used to extend the bass signaloutput range over two or more octaves. The extended octave range requires extra pins for lines 25, 33, 34, and 35 which provide potentials to control divider ratios to produce bass signals in the appropriate octave location. 9

Bass circuit 37 may include one or more bass frequency dividers in a chain driven by the signal on line 39 from bass logic and keying 13. Bass circuit 37 will further include keyers or modulators controlling the passage of outputs from the bass divider stages via cable 40 to output system and sound transducer 41 in response to voltages on lines 42 and 43 from bass logic and keying 13 and automatic rhythm 44 respectively. The keyers or modulators will include envelop shaping networks with storage for a sustain capability. Stop controls and tone forming circuits or filters may be included in bass circuit 37 and in output system and sound transducer 41. It will be recognized by those skilled in the art that mostpresent day electronic organs have bass circuits which include the apparatus of bass circuit 37 and which can be used to perform its functions. Bass circuit 37 and output system and sound transducer 41 will normally be part of any of the various organs with which the invention may be used.

When keyboard 14 is used, bass logic and keying 13 maintains the signal output on line 39 for the last actuated pedal when all pedals are released. The voltage on line 42 turns on the keyers or modulators of circuit 37 when any pedal is actuated. The voltage on line 42 is removed when all pedals are released but the keyers or modulators of bass circuit 37 include storage and can turn off gradually to provide a sustained decay of the outputs on cable 40 when this is desired. Automatic rhythm 44 may be used to operate the keyers or modulators of circuit 37 in rhythmic patterns while a pedal is being held, by having it apply appropriate control signals to line 43.

Keyboard 11 will normally be used with automatic rhythm 44 to provide two bass notes in rhythmic patterns. The signal on line 45 to bass logic and keying 13 from automatic rhythm 44 determines which of the two available bass notes will produce an output on line 39 at a time. If only one bass note is available, bass logic and keying 13 will ignore changes on line45 and continue to provide a corresponding signal for it on line 39. In this way, possible gaps in the rhythmic patterns are avoided. Keyboard 14 may also be used to provide two bass notes for selection by the control on line 45 although this would require more player skill.

FIGS. 2a, 2b, and 2c combine to show an embodiment in more detail than does'FlG. 1. As shown for the notes C and F sharp, keyboard 11 consists of playing keys 51 mechanically coupled to switches 52. While not shown, other switches may be mechanically coupled to playing keys 51 to perform the conventional functions for the musical instrument of which keyboard 11 is a part. Switches 52 are associated with the apparatus of this invention but they might also be used for other functions in the musical instrument as well. It will be recognized that playing keys 51 and switches 52 for the other notes would-be similar to those shown for C and F sharp.

Actuation of each playing key 51 pushes its associated switch 52 in contact with an associated bus. Switches 52 for the lowest octave range, are associated with bus 29.\', those for notes C through F in the second octave with bus 30.\', those for notes F sharp through B in the second octave with bus 31x, and those for the notes C through F in the thirdo'ctave with bus 32x. Switches 52 for the same note in all octave locations connect together as shown for the notes C and F sharp.

The common junction of leads from switches 52 for eachnote connect to a keyboard output through a resistor 12 and to ground through a resistor 53.

The pedal keyboard 14, unlike keyboard 11, need not perform functions in the musical instrument other than those associated with the apparatus presently disclosed. As shown for the notesC and F sharp in two octave locations, pedals 55 of keyboard 14 mechanically couple to associated switches 56. Switches 56 for the lowest octave contact bus 21.\' and those for the second octave contact bus 22.\' when their associated pedals 55 are actuated. Switches 56 for the same note in the two octaves connect to the keyboard output for the note.

The outputs for each note from keyboards 11 and 14 connect to the set input of an associatedlatch circuit 54 and to an input of an associated NAND gate 58. The other inputs to NAND gates 58 connect to line 19 and the reset inputs of latch circuits 54 connect to the outputs of their associated NAND gates 58. Latch circuits 54 are of a type, such as a Motorola P-channel MOS Static Logic Cell MH02LH flip flop, which sets and resets in response to a negative voltage on its set and reset inputs respectively. NAND gates 58 are of a type, such as a Motorola P-channel MOS Static Logic Cell MH02PS, which take ground potential to be a True input and a negative potential to be a False input. NAND gates 58 require both inputs to be at ground potential to produce a negative output to reset their associated latch circuits 54. If line 19 is at ground potential, latch circuits 54 will set and reset as theirrespective inputs from keyboards l1 and 14 go negative and ground, respectively. If line 19 is held negative, the outputs of AND gates 58 will remain at ground potential and latch circuits 54 will not be reset when their inputs from keyboards 11 and 14 go to ground potential.

When PEDAL/MANUAL switch 16 is in the position shown, line 19 is connected to the collector of transistor l8 and voltage is applied to busses 21x and 22x. Actuation of a pedal 55 of keyboard 14 for a note in either octave location will apply a negative potential to set the associated latch circuit 54. It will also cause transistor 18 to cut off and line 19 to go to ground potential. lf pedals 51 for all other notes are released, 'the other latch circuits 54 will have a negative potential applied to their reset inputs. It will be remembered that transistor 20 will be conducting if the actuated pedal 55 is associated with bus 22x and transistor 17 will be conducting whether it is associated with bus 22x or 21.\' and so cut off transistor 18. A

When the last actuated pedal 55 is released, transistor 17 suts off and transistor 18 immediately conducts. This pulls line 19 to the negative supply potential before the associated nand gate 58 can produce a negative output to reset the associated latch circuit 54. This occurs because latch circuit 54 and NAND gate 58 have a much slower rate'of response than bipolar transistors 17 and 18. (It is assumed the former will use MOS FET circuitry which is inherently slower than bipolar.) Latch circuits 54 will thus store an indication of the last actuated pedal 55 until the next'pedal is actuated. This provides for the normal electronic organ pedal sustain and pedal cancel functions without storage capacitors and discharge circuits.

When pedal manual switch 16 is in its other position, line 19 is connected to ground and voltage is applied to busses 29x, 30x, 31x, and 32.\' of keyboard 11. Actuation of a playing key 51 for a note in any octave'location on keyboard 11 will then apply a negative potential 6 to set the associated latch circuit 54. As line 19 is at ground potential, each NAND gate 58 inverts its other input so each latch circuit 54 resets as soon as the input from keyboards 11 and 14 goes to ground potential. Latch circuits 54 thus follow the actuation and release of their associated playing keys 51.

it will be remembered that transistors 26, 27, and 28 conduct when any playing key 51 associated with busses 30x, 31x, and 32x respectively is actuated. Lines 33 and 35 from the collectors of transistors 26 and 28 respectively go to the circuits of FIG. 2c to control functions which will be explained later. Lines 34 and 35 from the collectors of transistors 27 and 28 respectively and line 25 from the collector of transistor 20 all go to inputs of NAND gate 59. Resistors 60 connect the inputs of NAND gate 59 to ground to insure input at ground potential when transistors 27, 28, and 20 cut' off. The output of NAND gate 59 is inverted by inverter 61 and applied to the set input of latch circuit 62. NAND gate 63 is associated .with latch circuit 62 in the same way NAND gates 58 are associated with latch circuits 54 and also has its other input connected to line 19.

, Instead of being associated with a particular note, latch circuit 62 is associated with control of the octave range. The conduction of transistor 20, 27, or 28 sets latch circuit 62 by causing the output of NAND gate 59 to go to ground potential and the output of inverter 61 to a negative potential. As will later be explained, the outputs from latch circuit 62 for the set condition produce an upward shift in the bass signal by an octave interval. Like latch circuits 54, latch circuit 62 will store the condition produced by the last actuated pedal 55 when PEDAL/MANUAL switch 16 is in the position shown. The next actuated pedal 55 will reset latch circuit 62 unless it also causes transistor 20 to conduct and again apply a set input. When switch 16 is in its other position, latch circuit 62 follows the condition of transistors 27 and 28.

Each latch circuit 54 has a first output which is ground for the set condition and negative for the reset condition. Each latch circuit 54 further has a second output which is negative for the set condition and ground for the reset condition. Latch circuit 62 has similar first and secondoutputs. The first ,output of each latch circuit 54 is applied to the input of a NAND gate 70 on FIG. 2b which is associated with the same note as the latch circuit 54. The second output of each latchcircuit 54 is applied to the inputs of two NAND gates associated with the two adjacent notes on the down scale side. Circuit 54 for the note C, for example, has its first output applied to gate 70 for the note C and its second output applied to gates 70 for the notes B and A sharp. Circuit 54 for the note F sharp, for another example, has its first output applied to a gate 70 for-the note F sharp and its second output to gates 70 for the notes F and E.

Navel gates 70 will be considered to be operated when their output goes negative and this will occur when all of their inputs are at ground potential. A gate 70 can only operate when the latch circuit 54 from which it is receiving a first output is set and the latch circuits 54 from which it is receiving second outputs are reset. Each gate 70 also receives inhibiting inputs from the outputs of two other gates 70 and so also can operate only if both of the other gates 70 are not operated or if one is operated and a special condition obtains. The outputs of gates 70 for the notes G sharp I s 1 through B are applied through NO ,gates 71 and inverters 72 to the inhibiting inputs of gates for the notes C through D sharp respectively. The special condition results if any of these four inhibiting paths are blocked by the other inputs to NOR gates 71. Each gate 70 has its output applied to gates 70 for notes which are in minor third and third interval relation to its note. Gate 70 for the note C, for example, provides inputsto gates 70 for the notes D sharp and E. All outputs are directly applied except those going through NOR gates The net result of the enabling and inhibiting inputs from latch circuits 54 and the inhibiting inputs from other gates 70 to each gate 70 is that not more than two of gates 70 can be operated at a time for any combination of playing keys 51 or pedals 55 actuated. Further, the two operated gates 70 will be for notes which are related to each other as root and fifth, or root and diminished fifth. The addition of the four NOR gates 71 is necessary to prevent a possible oscillatory condition of gates 70 and permit the two operated gates 70 to also be for notes in the relation of root to augmented fifth, as will later be explained.

The results obtained for each possible combination of actuated playing keys 51 can be determined by listing each note enabled by an actuated playing key 51, by next marking off those inhibited by other actuated playing keys 51, and then by marking off those inhibited by other operated gates 70 until a stable combination of two operated gates 70 in obtained. It will be found that most combinations have only one stable combination of two operated gates 70. Each of three four part diminished chords consisting of the notes CD sharp F sharp A, C sharp EGA sharp, and DFG. sharp B has; two possible stable combinations of two operated gates 70. v

The four augmented chords consisting of the notes CEG sharp, C sharp FA, DF sharp Av sharp, and D sharp GB would not have a stable combination or state without NOR gates 71. Each gate 70 for a note of these chords would be inhibited by another and an oscillatory condition would obtain. NOR gates 71 block one of the inhibit paths in each of these chords so gates 70 for two of the notes can be operated in a stable combination. NOR gates 71 receive inputs from gates 70 for the notes G sharp through B and inputs from latch circuits 54 for the notes E through G respectively and provide inputs to gates 70 for the notes C through D sharp respectively. The inhibits from gates 70 for the notes G sharp through B are blocked when playing keys 51 for the notes Ethrough G respectively are actuated. Gates 70 for the notes C and G sharp, C sharp and A, D and A sharp, and D sharp and B will then be-operated for the respective chords.

Some idea of the results which will be obtained can be had by considering what happens with ch'ordsbased on a particular root. lf the note C is the root, for example, operation of its gate 70 will inhibit gates 70 for the notes D sharp and E. The note G is the perfect fifth and operation of its gate 70 inhibits gates 70 for the notes A sharp and B. Gates70 for the notes A sharp and B are also inhibited by latch circuit 54 for the note C. The proper root and fifth will thus be obtained for major and minor chords with seventh or major seventh parts.

The proper root will be obtained for these chords even, if the fifth is not played and the minor third, or third, or

seventh, or major seventh, could also not be played. If the note G is played. gates 70 for the notes F and F 8 sharp-will be inhibited and these notes could be added without affecting the result.

Playing of the note A :in place of A sharp or B changes the root from C to A. The combination of notes AC EG, for example, may be considered to be an A minor seventh chord or a C sixth chord. This apparatustakes it to be the former. Adding the notes D or C .sharp inhibits gate for the note C and so also changes the results. D is the ninth of C and further details concerning it may be of interest. If D sharp or E are also played, gate 70 for D will be inhibited by the input from the D sharp or E latch circuit 54 and only the gate 70 for the note G will be operated. If D sharp and E are not played, the combination will be considered a G chord with D as the fifth inhibiting C as the fourth just as G inhibited F above.

If F sharp is substituted for G so that the fifth is diminished, an operated gate 70 for F sharp will inhibit gates 70 for A and A sharp. The change is that A is now inhibited hence the sixth part can be played with the diminished chord. B remains inhibited by circuit 54 for C so the major seventh part could still be played as well as the sixth and seventh parts. It will be recognized, however, that the combination of CD sharp F sharp A is one of the three four part diminished chords and any of the notes could be taken as the root. lf gates 70 for thenotes C and F sharp operate first, they will inhibit gates 70 for the notes A and D sharp. If gates 70 for notes A and D sharp operate first, however, they will inhibit gates 70 for notes C and F sharp.

The choice of which pair of notes is to be taken as root, and fifth thus depends on the relative times of actuation of the respective playing keys 51. The other two four part diminished chords also have two stable conditions as previously discussed. As between C and F sharp, there is no basis for determining which is the root and which is the diminished fifth. The interval from either to the other is the same. The perfect fifth represented by G may also be replaced by an augmented fifth represented by G sharp. The substitution is made possible by the action of NOR gates 71 as previously discussed.

Each gate 70 has its output connected to the input of an associated NOR gate 73. The outputs of NOR gates 73 for the notes C through E are tied together as are also those for the notesF and F sharp, and those for the notes G through B. This arrangement is possible because the inhibiting action associated with gates 70 prevents more than one of NOR gates 73 in each group from being operated at a time so the outputs will not interfere with each other. Gates 73 for the notes C through F sharp receive tone signals for the corresponding notes C through F sharp on lines'38 from tone generators 36. Gates 73 for the notes G through B receivetone signals for the notes D through F sharp respectively from tone generators 36.

Dividing tone signals for the notes D through F sharp by three provides tone signals for the notes G through B respectively. Five input pins for tone signals from tonegenerators 36 can thus be saved by providing a capability to divide by three. It will be recognized that it would be somewhat easier to provide tone signals corresponding to the notes G through B where the number of pins required for input is not important. Cost for additional input pins and limitations on the number of pins possible for a package can, however, make the saving in the number of pins important.

The outputs of gates 70 for the notes C through E go to NAND gate 74. for F and F sharp to NAND gate 75, for G through B to NAND gate 76, for DD sharp GG sharp B to NAND gate 77, and for CC sharp FAA sharp to NAND gate 78. The outputs of NAND gates 74 through 78 are used in controllingthe passage of tone signals from NOR gates 73 on the inverting inputs of NOR gates 79, 80, and 81 to NOR gate 82. Gate 79 receives the outputs of NOR gate 73 for the notes C through E, NOR gate 80 the outputs of gates 73 for the notes F and F sharp, and NOR gate 81 the outputs of gates 73 for the notes G through B. i

If none of gates 79, 80, or 81 is receiving a tone signal on its inverting input from its respective group of gates 73, it is immaterial what control is applied. If only one of them is receiving a tone signal, it is essential that it be controlled to pass the signal. The inhibiting action associated with gates 70 is such that only two of gates 79, 80, and 81 can be receiving tone signals at the same time and the two may be composed of any of the possible combinations. A determination of which is the tone signal for the root part for the actuated combination of playing keys 51 or pedals 55 must be made if only a single bass tone is to be sounded, or if it is desired to sound the root part at particular locations in the rhythm pattern.

Gates 79, 80, and 81 receive control inputs from NOR gate 83, NAND gate 84, and OR gate 85 respectively. NAND gate 86 and OR gate 87 each receive an input from the output of NAND gate 74 and provide outputs to gates 84 and 85 respectively. NOR gate 88 and NAND gate 89 both receive an input from the output of gate 76 and provide outputs to gates 83 and 84 respectively. Gates 87 and 88 also receive an input from gate 75. NAND gate 90 provides inputs directly to gates 85 and 89 and through inverter 91 to gates 83 and 86. Gate 90 receives inputs from NAND gate 92 and from NOR gate 93 through inverter 95.

Negative inputs from the outputs of gates 83, 84, and 85 will enable NOR gates 79, 80, and 81 respectively to pass any tone signal present on their other input to gate 82. Gate 83 will provide a negative input to gate 79 while it is receiving a ground potential output from gate 88. Gate 88 will have a ground potential output while it is receiving negative inputs from gates 75 and 76. Gate 85 will similarly maintain a negative input to gate 81 while gate 87 is receiving negative inputs from gates 74 and 75. Gate 84 will maintain a negative input to gate 80 while it is receiving ground potential inputs from gates 86 and 89. These latter inputs will occur as long as the outputs from gates 74 and 76 remain negative.

If only one of gates 70 is operated, the associated gate 73 will pass a corresponding tone signal to the associated one of gates 79, 80, or 81. The output of the associated one of gates 74, 75, or 76 will go to ground potential but this will not affect the associated one of gates 79, 80, or 81 and the tone signal will be passed on to gate 82. This result will not be affected by the output from gate 90. If a gate 70 in each of two groups is operated at the same time, the results will depend on which groups are involved, and on the output of gate 90.

If a gate 70 for one of notes C through E and a gate 70 for one of notes F and F sharp are operated, corresponding tone signals will be passed to the inputs of gates 79 and 80 by the associated gates 73. The outputs of gates 74 and 75 will be at ground potential causing the outputs of gates 87 and 88 to be negative and the output of gate 86 to change as the output of inverter 91 changes. The output of gate 83 will go negative when the output of inverter 91 goes to ground potential and the output of gate 84 will go negative when the output of inverter 91 goes negative. The tone signals to gates 79 and 80 will thus be alternately passed to gate 82 as the output of inverter 91 goes alternately ground and negative.

If a gate for one of notes C through E and a gate 70 for one of notes G through B are operated at the same time, gates 79 and 81 will be receiving tone signals and the outputs of gates 74 and 76 will be at ground potential. Gate 83 will respond to the output of inverter 91 as in the just described case and gate 85 will similarly respond to the output of gate 90. Gates 79 and 81 will thus alternately pass their respective tone signal inputs to gate 82 as the output of gate 90 alternates out of phase with the output of inverter 91.

If a gate 70 for one of notes F and F sharp and a gate 70 for one of notes G through B are operated, gates 80 and 81 will receive tone signals and the outputs of gates 75 and 76 will be at ground potential. Gate will respond to the output of gate as before with its output going negative when its input from gate 90 goes to ground potential. The output of gate 89 will also go negative when the output of gate 90 goes to ground potential, causing the output of gate 84 to go to ground potential. The output of gate 84 goes negative when the output of gate 90 goes negative and so gates 80 and 81 alternately pass their respective tone signals to gate 82 when the output of gate 90 alternates.

It will be remembered that only one of gates 70 can be operated at a time in any group and that no more than two groups at a time a gate 70 operated. All possible combinations have thus been covered. If only one gate 70 is operated, its corresponding tone signal will be passed continuously to gate 82. When two groups each have an operated gate 70, only one tone signal will be passed at a time with the one passed being determined by the output of gate 90. If the output of gate 90 alternates, then the two tone signals will be passed alternately. The one of gates 79, 80, or 81 not receiving a tone signal will also be enabled and disabled in response to the output of gate 90 but this has no effect as there is no tone signal to pass.

If the output of gate 90 remains at ground potential, gate 81 will remain enabled and the tone signal corresponding to the one of gates 70 for the notes G through B operated will be passed to gate 82. Operation of a gate 70 for a note in either of the other two groups will not change the enabling of gate 81. If none of the gates 70 for the notes G through B is operated, the negative output of gate 76 to gate 89 and the negative output of inverter 91 to gate 86 will produce ground inputs to gate 84 causing it to enable gate 80. Gate 79 will be enabled only when the outputs of gates 75 and 76 are both negative. The group of gate 70 associated with notes G through B thus has priority over the other two groups and the group associated with notes F and F sharp has priority over the group associated with notes C through E.

if the output of gate 90 is held negative, the above priorities are reversed. Gate 79 will remain enabled by the negative output from gate 83 in response to the ground output from inverter 91 hence the group associated with notes C through E will have priority over the other two groupsv lfthe 'output of gate 74 remains negative, the output of gate 86 will be ground along with that of gate 89 which receives a negative input from 1 1 gate 90. Gate 84 will then have a negative output to enable gate 80 and give the group associated with notes F and F sharp priority over the one associated with notes G through B. Gate 81 will be enabled only if the outputs of gates 74 and 75 remain negative.

The output of gate 90 is responsive to the output of NAND gate 92 and the output of NOR gate 93 through inverter95. Gates 92 and 93 receive inputs from automatic rhythm 44 on line 45 and from NAND gate 94. NAND gate 94 receives inputs from gates 77 and 78, and'will have an output at ground potential except when gates 77 and 78 are each receiving an input from an operated one of gates 70. As gates 70 can be operated only two at a time for notes in root fifth, root diminished fifth, or root augmented fifth relation, gate 94 will have a negative output only for pairs of notes providing inputs to both of gates 78 and 79. These pairs consist of the following perfect fifth pairs of notes: CG, C sharp G sharp, DA, D sharp A sharp, and EB; for the following diminished fifth pairs of notes: C sharp G, and D sharp A; and for the following augmented fifth pairs of notes: CG sharp and DA sharp. The perfect fifth pairs are those in which the root is in the group of notes C through E and the other pairs can be considered to have their root in the same group.

The output of NAND gate 90 will be at ground potential if either of its inputs is negative. This occurs when both inputs to gates 92 and 93 are negative and when both are at ground potential. Gate 90 output will be negative when both its inputs are at ground potential. This occurs one input to gates 92 and 93 is negative and the other input is at ground potential. With the output of gate 94 and line 45 both at ground potential, the output of gate 90 will be at ground potential. The group of notes G through B will then have priority over the other two groups and notes F and F sharp will have priority over the group of notes C through E. If the output of gate 94 changes to negative, the output of gate 90 will also go negative and the priorities will be reversed with the group of notes C through E having priority over the other two groups, and notes F and F sharp having priority over notes G through B. Change of the voltage on line 45 will reverse the priorities for either output of gate 94.

The result of the control from gate 94 is that with line 45 at ground potential, only tone signals corresponding to the root of perfect fifth pairs will be passed to gate 82. Also, tone signals corresponding to the notes C sharp, D sharp, F sharp, G sharp, A sharp, and B will be passed to gate 82 for the diminished fifth pairs C sharp G, D sharp A, F sharp C, G sharp D, A sharp E, and BF respectively. Further, tone signals corresponding to the notes C, D, A, and B will be passed to gate 82 for the augmented fifth pairs CG sharp, DA sharp, AC sharp, and BD sharp respectively, as permitted by the shown arrangement of gates 71. The selection of these notes as the root for the diminished and augmented fifth pairs is arbitrary as either could be taken as the root. The tone signals for the other notes of the pairs will be passed to gate 82 when a negative potential is applied to line 45.

Controllable ratio frequency divider 96 receives the tone signals from the output of gate 82 and divides their frequency by two, three or four. NOR gate 97 receives one input from gate 85 and another from the output of gate 76 through inverter 98. The output of gate97 will be at ground potential when both inputs are negative, as will occur when gate 81 is passing a tone signal corresponding to an operated one of gates for the notes G through B. This condition requires the output of gate to be negative, the output of gate 76 to be at ground potential, and the output of inverter 98 to be negative. A ground potential output from gate 97 will cause frequency divider 96 to divide the tone signal from gate 81 by three. As previously explained, dividing the frequency of tone signals for the notes D through F sharp by three converts them to tone signals for the notes G through E.

The output of gate 97 will be negative when tone signals for any of the notes C through F sharp are passing gate 82. Frequency divider 96 will then divide by four if the output it is receiving from NAND gate 99 is negative, and by twoif the input is at ground potential. The tone signals on the output of frequency divider 96 for the notes C through F sharp will thus be higher or lower in frequency than those for the notes G through B depending on whether the output of gate 99 is ground or negative. The frequency will be higher when the highest pitch playing key 51 actuated is for one of the notes C through F in the second or third octaves and switch 16 is in the position which energizes manual keyboard 11. This condition will cause line 35 to be negative or line 33 to be negative while latch circuit 62 is reset. The output of gate 99 will be at ground potential when line 35 is negative or when line 33 and the output from latch circuit 62 to NOR gate 100 are both negative causing a negative output from inverter 101.

Controllable ratio frequency divider 102 receives the tone signal output of divider 96 and provides a tone signal output to bass circuit 37 via line 39. Frequency divider 102 is controlled by an output from latch circuit 62 to place its tone signal output in the proper range. Latch circuit 62 will be set if any playing key 51 is actuated for a note of higher pitch than E in the second octave while switch 16 is in the manual position or if a pedal 55 in the second octave is, or was the last, actuated while switch 16 is in the pedal position. Frequency divider 102 will divide the frequency of the tone signal from frequency divider 96 by two when latch circuit 62 is reset and and will pass it without change in frequency when latch circuit 62 is set.

The tone signals passed'by gate 82 may thus be divided in frequency by factors of two, three, four, six, and eight by frequency dividers 96 and 102 operating in cascade before being applied to bass circuit 37. The net result is that the tone signals on line 39 will follow the actuated playing keys 51 or pedals 55 in octave location. The tone signals could be restricted to an octave range by restricting frequency divider 96 to dividing by three or four and by holding frequency divider 102 to a single factor or eliminating it. Frequency divider 96 may be of a type, such as those disclosed in my US. Pat. No. 3,7l2,950, comprised of flip flops and control gates. Frequency divider 102 may be of the same type or may consist simply of a single flip flop and gates to select either its input or output for output. The bass circuits of most present day electronic organs can easily be combined with the other apparatus of the present invention to perform the functions of bass circuit 37. Reference will now be made to the bass circuit of FIG. 3 of US. Pat. No. 3,706,837 for a specific example of one way in which a prior art bass circuit can be incorporated in the apparatus of FIG. 2C as bass circuit 37. For this example, the tone signal on line 39 would be applied to line 80 of the aforereferenced circuit to drive its bass frequency divider 86. The base of transistor 122 of the referenced circuit would be connected through resistors to lines 42 and 43 and to a biasing potential such that transistor 122 would receive saturation drive when lines 42 and 43 were both at their most positive potential and nodrive if either was at its most negative potential. The operation of thereferenced circuit is such that the bass signal fromits divider 86 is passed to the output of'its transistor 94 when its transistor 122 is driven to saturation. The passed bass signal decreases gradually for a sustain effect as capaciter 128 of the referenced circuit discharges after transistor 122 cuts off. Cable 40 would be coupled to the output of the transistor 94.

When switch 16 is in the pedal position, line 42 is connected to the collector of transistor 18 and so is at a negative potential except when actuation of any of pedals 55 causes it to go to ground potential. When automatic rhythm 44 is off, line 43 will be at its most positive potential which may also be ground potential. Transistor 122 of the aforereferenced circuit will then be driven to saturation whenever line 42 goes to ground potential with actuation of any of pedals 55. This results in the bass signal being keyed to the output as previously described. It will be remembered that latch circuits 55 and 62 remain in the condition imposed by the last one of pedals 55 to be actuated so the corresponding tone signal will remain on line 39. The bass signal output will thus be sustained while the capacitor 128 discharges after all of pedals 55 are released and the transistor 122 cuts off.

When switch 16 is in the manual position, line 42 is held at ground potential. If automatic rhythm 44 is off, the transistor 122 will remain on and root tones of the manually played chords will sound as long as the playing keys 51 are held actuated. Release of all playing keys 51 removes the tone signal input to the line 80 and terminates the sounding. The fifth tones could be selected for sounding in place of the root tones by changing the voltage on line 45 from automatic rhythm 44 from ground potential to negative.

When automatic rhythm 44 is on, line 43 will be at a negative potential except when automatic rhythm 44 applies positive going pulses to it at rhythmic intervals. The positive going pulses will cause the transistor 122 to staturate when line 42 is at ground potential because switch 16 is in the manual position or because a pedal 55 is actuated. The result will be the sounding of bass tones in rhythmic patterns while playing keys 51 or pedals are held actuated. If playing keys 51 for chords with root and fifth parts are held actuated, automatic rhythm 44 can include the fifth part along with the root in the rhythmic soundings by controlling the voltage on line 45. The root and fifth parts will be sounded alternately, for example, if the voltage on line 45 is switched from one value to the other before each pulse on line 43.

Motorola P-channel Static Logic Cells MI-I02LH and MH02PS have already been mentioned as being suitable for latch circuits 54 and NAND gates 58 respectively. The same cells would also serve for latch circuit 62 and NAND gate 63. Cell MI-I02PS will also serve for NAND gates 75, 84, 86, 89, 90, 92, 94, and 99. Cell MHOSPS will serve for NAND gates 70, 74, 75, 76, 77, and 78 while NAND gate 59 may consist of cell MH03PS. Cell MH02SS will serve for NOR gates 71, 73, 83, 85, 87, 88, 93, 97, and 100 and for NOR gates 79, 80, and 81 with an inverter inserted in one input. Inverters 61, 72, 91, 95, 98, and 101 may consist of cell 14 MI-IOICD. It will be recognized by those skilled in the art that other circuits and other logic systems could also be used to implement the invention.

1 What is claimed is:

1. In an electronic musical instrument having a set of pedals for the notes of a musical scale, a set of tone generators, and an output system including a sound transducer, the combination of:

a. a set of latch circuits for the notes of a musical scale, each of said latch circuits having a set and a reset condition;

b. first means responsive to actuation of each of said pedals for setting the one of said latch circuits for the same note;

c. a frequency divider having its output coupled to said output system;

(1. means responsive to each of said latch circuits in the set condition for applying an output from one of said tone generators to said frequency divider;

e. means for producing a drive to reset all of said latch circuits while any of said pedals is actuated; and

f. means responsive to actuation of each of said pedals for inhibiting the resetting of said latch circuit for the same note.

2. The combination according to claim 1 including a set of playing keys for the notes of a musical scale; second means responsive to actuation of each of said playing keys for setting the one of said latching circuits for the same note; and means for switching said second setting means on or off; and wherein said producing means is also responsive to said switching means.

3. The combination according to claim 2 including means for limiting said applying means to one of said outputs at a time.

4. The combination according to claim 2 wherein said frequency divider can divide by different ratios and including means for controlling said frequency divider to divide by one ratio in response to actuation of any playing key for a note in one octave range and by another ratio in response to actuation of any playing key for a note in another octave range.

5. The combination according to claim 1 including means for limiting said applying means to one of said outputs at a time.

6. The combination according to claim 1 wherein said frequency divider can divide by different ratios and including means for controlling said frequency divider to divide by one ratio in response to actuation of any pedal for a note in one octave range and by another ratio in response to actuation of any pedal for a note in another octave range.

7. The combination according to claim 1 wherein the speed of response of said producing means to release of all pedals is faster than the response of said inhibiting means to the release of the pedal for the same note.

8. In an electronic musical instrument having a set of playing keys for the notes of a musical scale, a set of tone generators, and an output system including a sound transducer, the combination of:

a. a set of control gates for the notes of a musical scale;

b. means responsive to actuation of each of said playing keys for enabling the operation of the one of said control gates for the same note;

0. first means responsive to actuation of each of said playing keys for inhibiting another of said control gates for a note related to its note by a musical sevthird interval; 1

e. a frequency divider having its output coupled to said output system; and

f. means responsive to operation of each of said control gates for applying an output from one of said tone generators to said frequency divider.

9. The combination according to claim 8 including means for disabling one of said second inhibiting means responsive to actuation of a particular one of said playing keys. V Y

10. The combination according to claim 8 including means for limiting the response of said applying means to one of said control gates at a time.

11. The combination according to claim 10 incuding means for sensing the musical relation between the notes of operated pairs of said control gates to deterl6 mine to whichof said operated control gates said applying means will respond.

12. ,The combination according to claim 10 including means for switching the response of said applying means from one to another when more than one of said control gates is operated at the same time.

13. The combination according to claim 12 including an automatic rhythm device to operate said switching means in rhythmic patterns.

14. The combination according to claim 8 wherein said first inhibiting means inhibits said control gates for notes in seventh and major seventh musical relation to the note for each of said playing keys actuated and said second inhibiting means inhibits said control gates for notes in third and minor third musical relation to the note for each of said operated control gates.

15. The combination according to claim 14 including means for disabling one of said second inhibiting means responsive to actuation of a particular one of said playing keys. 

1. In an electronic musical instrument having a set of pedals for the notes of a musical scale, a set of tone generators, and an output system including a sound transducer, the combination of: a. a set of latch circuits for the notes of a musical scale, each of said latch circuits having a set and a reset condition; b. first means responsive to actuation of each of said pedals for setting the one of said latch circuits for the same note; c. a frequency divider having its output coupled to said output system; d. means responsive to each of said latch circuits in the set condition for applying an output from one of said tone generators to said frequency divider; e. means for producing a drive to reset all of said latch circuits while any of said pedals is actuated; and f. means responsive to actuation of each of said pedals for inhibiting the resetting of said latch circuit for the same note.
 2. The combination according to claim 1 including a set of playing keys for the notes of a musical scale; second means responsive to actuation of each of said playing keys for setting the one of said latching circuits for the same note; and means for switching said second setting means on or off; and wherein said producing means is also responsive to said switching means.
 3. The combination according to claim 2 including means for limiting said applying means to one of said outputs at a time.
 4. The combination according to claim 2 wherein said frequency divider can divide by different ratios and including means for controlling said frequency divider to divide by one ratio in response to actuation of any playing key for a note in one octave range and by another ratio in response to actuation of any playing key for a note in another octave range.
 5. The combination according to claim 1 including means for limiting said applying means to one of said outputs at a time.
 6. The combination according to claim 1 wherein said frequency divider can divide by different ratios and including means for controlling said frequency divider to divide by one ratio in response to actuation of any pedal for a note in one octave range and by another ratio in response to actuation of any pedal for a note in another octave range.
 7. The combination according to claim 1 wherein the speed of response of said producing means to release of all pedals is faster than the response of said inhibiting means to the release of the pedal for the same note.
 8. In an electronic musical instrument having a set of playing keys for the notes of a musical scale, a set of tone generators, and an output system including a sound transducer, the combination of: a. a set of control gates for the notes of a musical scale; b. means responsive to actuation of each of said playing keys for enabling the operation of the one of said control gates for the same note; c. first means responsive to actuation of each of said playing keys for inhibiting another of said control gates for a note related to its note by a musical seventh interval; d. second means responsive to operation of each of said control gates for inhibiting another of said gates for a note related to its note by a musical third interval; e. a frequency divider having its output coupled to said output system; and f. means responsive to operation of each of said control gates for applying an output from one of said tone generators to said frequency divider.
 9. The combination according to claim 8 including means for disabling one of said second inhibiting means responsive to actuation of a particular one of said playing keys.
 10. The combination according to claim 8 including means for limiting the response of said applying means to one of said control gates at a time.
 11. The combination according to claim 10 incuding means for sensing the musical relation between the notes of operated pairs of said control gates to determine to which of said operated control gates said applying means will respond.
 12. The combination according to claim 10 including means for switching the response of said applying means from one to another when more than one of said control gates is operated at the same time.
 13. The combination according to claim 12 including an automatic rhythm device to operate said switching means in rhythmic patterns.
 14. The combination according to claim 8 wherein said first inhibiting means inhibits said control gates for notes in seventh and major seventh musical relation to the note for each of said playing keys actuated and said second inhibiting means inhibits said control gates for notes in third and minor third musical relation to the note for each of said operated control gates.
 15. The combination according to claim 14 including means for disabling one of said second inhibiting means responsive to actuation of a particular one of said playing keys. 